Generally, automatic doors have several types of known control apparatus, including the double-rail or mono-rail reciprocal type driven by a chain and sprocket, the double-rail or mono-rail rotational type driven by a rack and pinion, and the rotational type driven by pair of bevel gears and a swinging arm.
Specifically, there are two types of automatic door control apparatus which are considered related to the present invention. The first type has its motor and speed reducing mechanism disposed in a door post to facilitate maintenance, but this type of apparatus is difficult to install. The second type has its motor and speed reducing mechanism disposed under ground level, but this type of apparatus is easily damaged by moisture.